Analysis of the reliability for the 132/66/22 KV distribution network within Eskom’s Eastern Cape operating unit
- Authors: Pantshwa, Athini
- Date: 2018
- Subjects: Electric power transmission -- Reliability , Electric power distribution Electric power Electric power systems
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/34722 , vital:33429
- Description: A stable and reliable electrical power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customer’s reliability requirements are met and that the regulators requirements are satisfied at the lowest possible cost. It is known fact around the world that 90% of the customer service interruptions are caused due to failure in distribution system. Therefore, it is worth considering reliability assessments as it provides an opportunity to incorporate the cost or losses incurred by the utilities customer because of power failure. This must be considered in the planning and operating practices. The system modelling and simulation study is carried out on one of the district’s distribution system which consists of 132 kV, 66 kV and 22 kV network in Aliwal North Sector ECOU. The reliability assessment is done on the 22, 66 and 132 kV system to assess the performance of the present system and predictive reliability analysis for the future system considering load growth and system expansion. The alternative which gives low SAIDI, SAIFI and minimum breakeven costs is being assessed and considered. The reliability of 132 kV system could be further improved by constructing a new 132 kV line from a different source of supply and connecting with line coming from another district (reserve) at reasonable break-even cost. The decision base could be further improved by having Aliwal North Sector context interruption cost. However, the historical data which may be used in Aliwal North Sector to acquire interruption costs from the customers are being proposed. The focus should be on improving the power quality on constrained networks first, then the reliability. Therefore, for the Aliwal North power system network it is imperative that Eskom invest on the reliability of this network. This dissertation also analysed load reflected economic benefit versus performance expectations that should be optimized through achieving a balance between network performance (SAIDI) improvement, and total life cycle cost (to Eskom as well as the economy). Reliability analysis conducted in this dissertation used Aliwal North power system network as a case study; the results proved that the system is vulnerable to faults, planned and unplanned outages. Reliability evaluation studies were conducted on the system using DigSilent software in conjunction with FME. These two models gave accurate results with acceptable variance in most indices except for the ENS where the variance was quite significant. It can be concluded that DigSilent results are the most accurate results in all three reliability evaluation scenarios for the Aliwal North Power System, best interpretation being that of DigSilent.
- Full Text:
- Date Issued: 2018
- Authors: Pantshwa, Athini
- Date: 2018
- Subjects: Electric power transmission -- Reliability , Electric power distribution Electric power Electric power systems
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/34722 , vital:33429
- Description: A stable and reliable electrical power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customer’s reliability requirements are met and that the regulators requirements are satisfied at the lowest possible cost. It is known fact around the world that 90% of the customer service interruptions are caused due to failure in distribution system. Therefore, it is worth considering reliability assessments as it provides an opportunity to incorporate the cost or losses incurred by the utilities customer because of power failure. This must be considered in the planning and operating practices. The system modelling and simulation study is carried out on one of the district’s distribution system which consists of 132 kV, 66 kV and 22 kV network in Aliwal North Sector ECOU. The reliability assessment is done on the 22, 66 and 132 kV system to assess the performance of the present system and predictive reliability analysis for the future system considering load growth and system expansion. The alternative which gives low SAIDI, SAIFI and minimum breakeven costs is being assessed and considered. The reliability of 132 kV system could be further improved by constructing a new 132 kV line from a different source of supply and connecting with line coming from another district (reserve) at reasonable break-even cost. The decision base could be further improved by having Aliwal North Sector context interruption cost. However, the historical data which may be used in Aliwal North Sector to acquire interruption costs from the customers are being proposed. The focus should be on improving the power quality on constrained networks first, then the reliability. Therefore, for the Aliwal North power system network it is imperative that Eskom invest on the reliability of this network. This dissertation also analysed load reflected economic benefit versus performance expectations that should be optimized through achieving a balance between network performance (SAIDI) improvement, and total life cycle cost (to Eskom as well as the economy). Reliability analysis conducted in this dissertation used Aliwal North power system network as a case study; the results proved that the system is vulnerable to faults, planned and unplanned outages. Reliability evaluation studies were conducted on the system using DigSilent software in conjunction with FME. These two models gave accurate results with acceptable variance in most indices except for the ENS where the variance was quite significant. It can be concluded that DigSilent results are the most accurate results in all three reliability evaluation scenarios for the Aliwal North Power System, best interpretation being that of DigSilent.
- Full Text:
- Date Issued: 2018
Analysis of the role of unions in health services delivery at Uitenhage district hospital
- Authors: Tshamase, Nozibele Yvonne
- Date: 2018
- Subjects: Public health Health services accessibility Labor unions
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/12348 , vital:39255
- Description: Purpose: According to Khan and Khan (2011:56), a trade union is an organization of employee tasked with activities which include negotiating on behalf of their members for “pay and conditions of employment”. Several authors have purported that these roles extend beyond ensuring not only that the rights of workers are not violated and that their working environment complies with health and safety standards, but also that unions may have an effect on management practices, generally and specifically, on efficiencies and performance (Zulu, 2009; McGuire, 2011; & Dhliwayo, 2012). Health care workers including professionals are organised by the unions in a bid to influence social and economic reforms in the South African democracy. The main aim of this study was to examine the role of public sector unions and how they exercise their functions in delivery of health services Method: A qualitative research method based on phenomenological and case approaches was applied. Semi-structured interviews with open ended questions were used to prompt discussions. Documents were used to obtain complementary data. Senior managers, middle managers, union/employee representatives and employees who are members of the unions in the district hospital of Nelson Mandela Bay health district constituted the target population. Purposive non-probability sampling, which was the preferred method for this study, yielded 16 participants. Results Analysis followed Creswell’s thematic analysis involving coding responses categorising them and identifying themes. This followed repeated and thorough listening to the recorded interviews and transcribing. Themes identified were organisational functioning in line with the service delivery context; worker’s rights protection; negotiating better service conditions; implementing legislation, policies and resolutions; union-management interaction; engaging in strikes and impact on services delivery. Conclusion and Recommendations: The study found that the presence of unions in health care services was necessary because there are various categories of employees – working class – whose interests must be served. The role of the unions leaned heavily towards protection of the rights of the workers. As far as the observation of legislation is concerned, the unions demonstrated knowledge of the legislation applicable to the health care personnel, that is, the BCEA, the LRA and the PSA. The study found that unions were a hindrance to health services delivery in their quest to exercise voice monopoly. The unions tended to exert undue influence on management resulting in lack of discipline and dereliction of duty. The strike actions compromised quality of health care and the rights of citizens to access health care. There was no active participation nor positive contributions in committees where advancement of service delivery standards were deliberated and promoted. Recommendations included training of shop stewards; capacitation and training of managers, and development and communication of departmental labour relations policies.
- Full Text:
- Date Issued: 2018
- Authors: Tshamase, Nozibele Yvonne
- Date: 2018
- Subjects: Public health Health services accessibility Labor unions
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/12348 , vital:39255
- Description: Purpose: According to Khan and Khan (2011:56), a trade union is an organization of employee tasked with activities which include negotiating on behalf of their members for “pay and conditions of employment”. Several authors have purported that these roles extend beyond ensuring not only that the rights of workers are not violated and that their working environment complies with health and safety standards, but also that unions may have an effect on management practices, generally and specifically, on efficiencies and performance (Zulu, 2009; McGuire, 2011; & Dhliwayo, 2012). Health care workers including professionals are organised by the unions in a bid to influence social and economic reforms in the South African democracy. The main aim of this study was to examine the role of public sector unions and how they exercise their functions in delivery of health services Method: A qualitative research method based on phenomenological and case approaches was applied. Semi-structured interviews with open ended questions were used to prompt discussions. Documents were used to obtain complementary data. Senior managers, middle managers, union/employee representatives and employees who are members of the unions in the district hospital of Nelson Mandela Bay health district constituted the target population. Purposive non-probability sampling, which was the preferred method for this study, yielded 16 participants. Results Analysis followed Creswell’s thematic analysis involving coding responses categorising them and identifying themes. This followed repeated and thorough listening to the recorded interviews and transcribing. Themes identified were organisational functioning in line with the service delivery context; worker’s rights protection; negotiating better service conditions; implementing legislation, policies and resolutions; union-management interaction; engaging in strikes and impact on services delivery. Conclusion and Recommendations: The study found that the presence of unions in health care services was necessary because there are various categories of employees – working class – whose interests must be served. The role of the unions leaned heavily towards protection of the rights of the workers. As far as the observation of legislation is concerned, the unions demonstrated knowledge of the legislation applicable to the health care personnel, that is, the BCEA, the LRA and the PSA. The study found that unions were a hindrance to health services delivery in their quest to exercise voice monopoly. The unions tended to exert undue influence on management resulting in lack of discipline and dereliction of duty. The strike actions compromised quality of health care and the rights of citizens to access health care. There was no active participation nor positive contributions in committees where advancement of service delivery standards were deliberated and promoted. Recommendations included training of shop stewards; capacitation and training of managers, and development and communication of departmental labour relations policies.
- Full Text:
- Date Issued: 2018
Analysis of the security and reliability of packet transmission in Wireless Mesh Networks (WMNs) : a case study of Malicious Packet drop attack
- Adeniji, Victor Oluwatobiloba
- Authors: Adeniji, Victor Oluwatobiloba
- Date: 2018
- Subjects: Wireless communication systems Mobile communication systems
- Language: English
- Type: Thesis , Masters , Computer Science
- Identifier: http://hdl.handle.net/10353/17450 , vital:40969
- Description: Wireless Mesh Networks (WMNs) are known for possessing good attributes such as low up-front cost, easy network maintenance, and reliable service coverage. This has largely made them to be adopted in various areas such as; school campus networks, community networking, pervasive healthcare, office and home automation, emergency rescue operations and ubiquitous wireless networks. The routing nodes are equipped with self-organized and self-configuring capabilities. The routing mechanisms of WMNs depend on the collaboration of all participating nodes for reliable network performance. However, it has been noted that most routing algorithms proposed for WMNs in the last few years are designed with the assumption that all the participating nodes will collaboratively be involved in relaying the data packets originated from a source to a multi-hop destination. Such design approach exposes WMNs to vulnerability such as malicious packet drop attack. Therefore, it is imperative to design and implement secure and reliable packet routing mechanisms to mitigate this type of attack. While there are works that have attempted to implement secure routing approach, the findings in this research unearthed that further research works are required to improve the existing secure routing in order to provide more secure and reliable packet transmission in WMNs, in the event of denial of service (DoS) attacks such black hole malicious pack drop attack. This study further presents an analysis of the impact of the black hole malicious packet drop attack with other influential factors in WMNs. In the study, NS-3 simulator was used with AODV as the routing protocol. The results show that the packet delivery ratio and throughput of WMN under attack decreases sharply as compared to WMN free from attack.
- Full Text:
- Date Issued: 2018
- Authors: Adeniji, Victor Oluwatobiloba
- Date: 2018
- Subjects: Wireless communication systems Mobile communication systems
- Language: English
- Type: Thesis , Masters , Computer Science
- Identifier: http://hdl.handle.net/10353/17450 , vital:40969
- Description: Wireless Mesh Networks (WMNs) are known for possessing good attributes such as low up-front cost, easy network maintenance, and reliable service coverage. This has largely made them to be adopted in various areas such as; school campus networks, community networking, pervasive healthcare, office and home automation, emergency rescue operations and ubiquitous wireless networks. The routing nodes are equipped with self-organized and self-configuring capabilities. The routing mechanisms of WMNs depend on the collaboration of all participating nodes for reliable network performance. However, it has been noted that most routing algorithms proposed for WMNs in the last few years are designed with the assumption that all the participating nodes will collaboratively be involved in relaying the data packets originated from a source to a multi-hop destination. Such design approach exposes WMNs to vulnerability such as malicious packet drop attack. Therefore, it is imperative to design and implement secure and reliable packet routing mechanisms to mitigate this type of attack. While there are works that have attempted to implement secure routing approach, the findings in this research unearthed that further research works are required to improve the existing secure routing in order to provide more secure and reliable packet transmission in WMNs, in the event of denial of service (DoS) attacks such black hole malicious pack drop attack. This study further presents an analysis of the impact of the black hole malicious packet drop attack with other influential factors in WMNs. In the study, NS-3 simulator was used with AODV as the routing protocol. The results show that the packet delivery ratio and throughput of WMN under attack decreases sharply as compared to WMN free from attack.
- Full Text:
- Date Issued: 2018
Analysis of VAT compliance challenges in municipalities
- Authors: Nkonzombi, Linda
- Date: 2018
- Subjects: Value-added tax -- South Africa , Income tax -- South Africa Income tax -- Law and legislation -- South Africa Taxation -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/33429 , vital:32864
- Description: The study was carried out to identify challenges that municipalities have with becoming Value Added Tax (‘VAT’) compliant. This study has been prompted by the ongoing findings reported by the Auditor General (‘AG’) in its audit reports. The increasing demand on the services of tax consultants also suggests that municipalities are having challenges in independently fulfilling their tax obligations. It was found that municipalities are often challenged with the application of the following VAT sections: The VAT apportionment methodology, section 8(27) dealing with unallocated payments, VAT reconciliations and claiming of VAT on invalid documentation and where VAT credits are denied. The main causes of non-compliance were identified as complexity of the tax laws, interpretation issues, behavioural attitude, lack of technical expertise within municipalities, and the fact that VAT is a self-assessed tax. Based on the findings of the study, it is recommended that all municipalities should be required to have a designated tax team to handle the tax matters of a municipality. The municipalities’ governing body, South African Local Government Association (‘SALGA’), should consider introducing penalties to non-VAT compliant municipalities. SARS should establish ‘customer relationships’ with the municipalities.
- Full Text:
- Date Issued: 2018
- Authors: Nkonzombi, Linda
- Date: 2018
- Subjects: Value-added tax -- South Africa , Income tax -- South Africa Income tax -- Law and legislation -- South Africa Taxation -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/33429 , vital:32864
- Description: The study was carried out to identify challenges that municipalities have with becoming Value Added Tax (‘VAT’) compliant. This study has been prompted by the ongoing findings reported by the Auditor General (‘AG’) in its audit reports. The increasing demand on the services of tax consultants also suggests that municipalities are having challenges in independently fulfilling their tax obligations. It was found that municipalities are often challenged with the application of the following VAT sections: The VAT apportionment methodology, section 8(27) dealing with unallocated payments, VAT reconciliations and claiming of VAT on invalid documentation and where VAT credits are denied. The main causes of non-compliance were identified as complexity of the tax laws, interpretation issues, behavioural attitude, lack of technical expertise within municipalities, and the fact that VAT is a self-assessed tax. Based on the findings of the study, it is recommended that all municipalities should be required to have a designated tax team to handle the tax matters of a municipality. The municipalities’ governing body, South African Local Government Association (‘SALGA’), should consider introducing penalties to non-VAT compliant municipalities. SARS should establish ‘customer relationships’ with the municipalities.
- Full Text:
- Date Issued: 2018
Antecedents and outcomes of service encounters in the restaurant industry in Zimbabwe
- Authors: Mukucha, Paul
- Date: 2018
- Subjects: Consumer behavior , Hospitality industry -- Zimbabwe -- Management Management -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/32949 , vital:32479
- Description: This study aimed to determine the antecedents and outcomes of service encounter experiences of patrons in the restaurant industry in Zimbabwe. In addition, the study aimed to test the strength of the relationships between service encounter experiences and the selected antecedents, and outcomes. Service encounter experiences were investigated to contribute to the success of restaurants in Zimbabwe. The study presented literature on the restaurant industry in Zimbabwe. The literature explored the types of restaurant businesses that are operating in Zimbabwe, the contribution of the restaurant industry to the national economy, the attractiveness of the restaurant industry and the market structure of the restaurant industry. The literature also revealed that the restaurant industry immensely contributes to the national economy of Zimbabwe through employment creation and statutory payments. It was further revealed that the restaurant industry in Zimbabwe is attractive because there are little entry and exit barriers, and there is some degree of differentiation of service delivery. The contemporary issues that affect the restaurant industry in Zimbabwe cut across several macro business factors, and were identified as political, economic, social, technological, legal and environmental factors. Theories and literature were considered, and the study extensively presented content related to the postulated relationships among the study’s variables, namely the specified antecedents of service encounter experiences which are the variables service contact levels, ambience factors, service delivery quality, and typology of patrons; and the selected outcomes of service encounter experiences, namely patronage retention, re-patronage retention, and patronage loyalty. A synthesis of how all the study constructs are interrelated, culminating with the proposed conceptual model, were presented. The proposed conceptual model that captures service encounter experiences and its possible antecedents and outcomes, depicted a series of hypotheses. The hypotheses presented were developed by using extant theoretical and empirical literature. The study further presented the research methodology, and the results of this study. This explanatory study followed a quantitative survey research design and 400 restaurant patrons in Zimbabwe were respondents to the study’s questionnaire. Descriptive statistics were calculated. In addition, using exploratory factor analyses results, the conceptual framework was updated, and further inferential statistics were computed. These statistics included a reliability analysis, correlation analysis and regression analyses to statistically test the proposed relationships. The empirical results revealed that all the postulated independent variables, except the variable service contact levels, are positively and significantly related to the patrons’ service encounter experiences. Furthermore, the study revealed that the patrons’ service encounter experiences significantly influence two specified dependent variables namely re-patronage intention and patronage loyalty. Patronage retention, which was one of the hypothesised outcomes of service encounter experiences, was eliminated from the proposed conceptual model during the measurement scale validation phase as almost all of its items loaded onto the patronage loyalty factor. This suggested the absence of a conceptual distinction between patronage retention and patronage loyalty. The study concluded that the levels of the patrons’ service encounter experiences in the restaurant industry in Zimbabwe are high as a result of higher levels of the postulated antecedents such as ambience factors, service delivery quality and typology of patrons. However, the levels of contact in restaurants did not have any significant impact on the patrons’ service encounter experiences. The study also concluded that eliciting pleasant service encounter experiences generates higher levels of re-patronage retention and patronage loyalty. The conclusions generated in this study subsequently led to a number of recommendations for restaurants in Zimbabwe. The study also contributed by either closing or clarifying many research gaps as well as by developing a hypothetical model and measuring instrument. This study was the first to show how ambience factors, service quality delivery and the typology of patrons, based on their personality traits, could positively influence the service encounter experiences of Zimbabwean restaurants’ patrons. Furthermore, the study confirms that in the restaurant industry, the patronage retention construct is conceptually the same as the patronage loyalty construct. Moreover, restaurant businesses must exploit the differences in their patrons’ dispositions in order to enhance service encounter experiences through providing differentiated service offerings.
- Full Text:
- Date Issued: 2018
- Authors: Mukucha, Paul
- Date: 2018
- Subjects: Consumer behavior , Hospitality industry -- Zimbabwe -- Management Management -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/32949 , vital:32479
- Description: This study aimed to determine the antecedents and outcomes of service encounter experiences of patrons in the restaurant industry in Zimbabwe. In addition, the study aimed to test the strength of the relationships between service encounter experiences and the selected antecedents, and outcomes. Service encounter experiences were investigated to contribute to the success of restaurants in Zimbabwe. The study presented literature on the restaurant industry in Zimbabwe. The literature explored the types of restaurant businesses that are operating in Zimbabwe, the contribution of the restaurant industry to the national economy, the attractiveness of the restaurant industry and the market structure of the restaurant industry. The literature also revealed that the restaurant industry immensely contributes to the national economy of Zimbabwe through employment creation and statutory payments. It was further revealed that the restaurant industry in Zimbabwe is attractive because there are little entry and exit barriers, and there is some degree of differentiation of service delivery. The contemporary issues that affect the restaurant industry in Zimbabwe cut across several macro business factors, and were identified as political, economic, social, technological, legal and environmental factors. Theories and literature were considered, and the study extensively presented content related to the postulated relationships among the study’s variables, namely the specified antecedents of service encounter experiences which are the variables service contact levels, ambience factors, service delivery quality, and typology of patrons; and the selected outcomes of service encounter experiences, namely patronage retention, re-patronage retention, and patronage loyalty. A synthesis of how all the study constructs are interrelated, culminating with the proposed conceptual model, were presented. The proposed conceptual model that captures service encounter experiences and its possible antecedents and outcomes, depicted a series of hypotheses. The hypotheses presented were developed by using extant theoretical and empirical literature. The study further presented the research methodology, and the results of this study. This explanatory study followed a quantitative survey research design and 400 restaurant patrons in Zimbabwe were respondents to the study’s questionnaire. Descriptive statistics were calculated. In addition, using exploratory factor analyses results, the conceptual framework was updated, and further inferential statistics were computed. These statistics included a reliability analysis, correlation analysis and regression analyses to statistically test the proposed relationships. The empirical results revealed that all the postulated independent variables, except the variable service contact levels, are positively and significantly related to the patrons’ service encounter experiences. Furthermore, the study revealed that the patrons’ service encounter experiences significantly influence two specified dependent variables namely re-patronage intention and patronage loyalty. Patronage retention, which was one of the hypothesised outcomes of service encounter experiences, was eliminated from the proposed conceptual model during the measurement scale validation phase as almost all of its items loaded onto the patronage loyalty factor. This suggested the absence of a conceptual distinction between patronage retention and patronage loyalty. The study concluded that the levels of the patrons’ service encounter experiences in the restaurant industry in Zimbabwe are high as a result of higher levels of the postulated antecedents such as ambience factors, service delivery quality and typology of patrons. However, the levels of contact in restaurants did not have any significant impact on the patrons’ service encounter experiences. The study also concluded that eliciting pleasant service encounter experiences generates higher levels of re-patronage retention and patronage loyalty. The conclusions generated in this study subsequently led to a number of recommendations for restaurants in Zimbabwe. The study also contributed by either closing or clarifying many research gaps as well as by developing a hypothetical model and measuring instrument. This study was the first to show how ambience factors, service quality delivery and the typology of patrons, based on their personality traits, could positively influence the service encounter experiences of Zimbabwean restaurants’ patrons. Furthermore, the study confirms that in the restaurant industry, the patronage retention construct is conceptually the same as the patronage loyalty construct. Moreover, restaurant businesses must exploit the differences in their patrons’ dispositions in order to enhance service encounter experiences through providing differentiated service offerings.
- Full Text:
- Date Issued: 2018
Anthropogenic effects on sustainability of fish biodiversity in Tyume River, Eastern Cape, South Africa
- Authors: Kinya, Jane Njeri
- Date: 2018
- Subjects: Fishes--Behavior Fishes--Physiology Biotic communities
- Language: English
- Type: Thesis , Doctoral , Zoology
- Identifier: http://hdl.handle.net/10353/11740 , vital:39102
- Description: To determine the anthropogenic effects on the sustainability of fish biodiversity in Tyhume River, a mixture of ecological, economic and institutional parameters were used. To measure ecological parameters, 10 study sites were selected to represent varying intensities of anthropogenic effects on habitat, to represent typical river zones, and to correspond with historical survey sites for trend analysis. In these study sites, habitat characteristics that represent geomorphology (habitat quantity), water quality and ‘alien’ (non–native) fishes were used to determine anthropogenic effects on habitat and fish assemblage. The measured geomorphology characteristics included current velocity, wetted width and depth. The water quality characteristics used were temperature, pH and conductivity. To determine the effects of native and non-native on indigenous fish species in situ, electro fishing was used in riffles, small pools and runs; as well, in situ seine-netting was done in pools. The riches of river fish species was measured, using numbers abundance and longitudinal distribution indices. It was established that only 11percent of the Tyhume River habitat was relatively near natural, while 89percent exhibited anthropogenic habitat modification. Three major sources ofanthropogenic modification on habitat were identified. The major contributor of anthropogenic effects was Binfield Park Dam which accounted for 43percent of modification. The second source of anthropogenic effects on habitat was Alice urban area where storm water runoff accounted for 28percent of modification. Agricultural and livestock grazing, the third anthropogenic effect, accounted for 18percent of modification. The Eastern Cape Rocky, Sandelia bainsii Castelnau, 1861 and Border Barb, Barbus trevelyani Günther, 1868, exhibited reduced distribution. B. trevelyani longitudinal distribution was less than 25 km along the river continuum, with sporadic presence in the sandy foothills. S. bainsii was not found in the Lowland Zone, while previously this species extended from the mountainous zone to the confluence of the Tyhume and Keiskamma Rivers in the Lowland Zone. These indices supported the homogenization theory, as reflected by increased dissimilarity for two indigenous fish species, S. bainsii and B. trevelyani, among study sites. S. bainsii was previously distributed from source to confluence, while B. trevelyani recorded a 50percent decline at the study site below the Binfield Park Dam. To assign economic value to ecosystem services and assess post Rio-institutional parameters two hypothetical scenarios were developed from the ecological survey; one depicting current conditions and another depicting improved ecosystem services. Using a structured interview questionnaire, five ecosystem services in need of restoration were described to respondents. Applying the contingent valuation method respondents were asked a dichotomous choice question on willingness to pay (WTP). Results of the economic study from 209 personal interviews revealed, individuals were willing to pay an additional R 32.00 on their monthly water bill or R 384.00 annually. Generalizing this to 2 829 households living in the Alice and Ntselamanzi urban areas, a total value of R 1 086 336 would be realized annually. This was equivalent to the Nkonkobe Municipality annual budget for storm water management in Alice urban area. Costs/benefits revealed a positive net present value (NPV) = 1, which, in line with economic theory, meant gainers were able to compensate losers The institutional part of the economic survey sought to determine the effects of post Rio Earth Summit institutional measures on sustainable management of Tyhume River fish assemblage. A desk review of Rio Declaration and three South African statutes were used namely; Constitution Act 108 of 1996 (South African Constitution 1996); the National Environmental Management Biodiversity Act No. 10 of 2004 (NEMBA 2004), the National Environmental Management Act (NEMA) No. 107 of 1998 (NEMA 1998), and the National Water Act No. 36 of 1998 (NWA 1998). The Institutional and Analytic Development (IAD) Framework, coupled with requirements for sustainability of Multiple Use Resource Domains were used for the analysis. De Jure, the statutes had internationalization of environmental costs through “polluter pays principle”, while sustainable use was the overarching goal. De facto, the community participation, a requisite of post Rio measures, was low; however 89percent of community respondents were willing to join an environmental conservation group. This, coupled with the fact that 77percent of those interviewed supported the establishment of a Tyhume River Restoration Fund, provided scope for a broad based community participation framework This study contributes to sustainable use of Tyhume River and other lotic systems by generating information on the link between anthropogenic effects on fish biodiversity, economic value of ecosystems services and institutional mechanisms.
- Full Text:
- Date Issued: 2018
- Authors: Kinya, Jane Njeri
- Date: 2018
- Subjects: Fishes--Behavior Fishes--Physiology Biotic communities
- Language: English
- Type: Thesis , Doctoral , Zoology
- Identifier: http://hdl.handle.net/10353/11740 , vital:39102
- Description: To determine the anthropogenic effects on the sustainability of fish biodiversity in Tyhume River, a mixture of ecological, economic and institutional parameters were used. To measure ecological parameters, 10 study sites were selected to represent varying intensities of anthropogenic effects on habitat, to represent typical river zones, and to correspond with historical survey sites for trend analysis. In these study sites, habitat characteristics that represent geomorphology (habitat quantity), water quality and ‘alien’ (non–native) fishes were used to determine anthropogenic effects on habitat and fish assemblage. The measured geomorphology characteristics included current velocity, wetted width and depth. The water quality characteristics used were temperature, pH and conductivity. To determine the effects of native and non-native on indigenous fish species in situ, electro fishing was used in riffles, small pools and runs; as well, in situ seine-netting was done in pools. The riches of river fish species was measured, using numbers abundance and longitudinal distribution indices. It was established that only 11percent of the Tyhume River habitat was relatively near natural, while 89percent exhibited anthropogenic habitat modification. Three major sources ofanthropogenic modification on habitat were identified. The major contributor of anthropogenic effects was Binfield Park Dam which accounted for 43percent of modification. The second source of anthropogenic effects on habitat was Alice urban area where storm water runoff accounted for 28percent of modification. Agricultural and livestock grazing, the third anthropogenic effect, accounted for 18percent of modification. The Eastern Cape Rocky, Sandelia bainsii Castelnau, 1861 and Border Barb, Barbus trevelyani Günther, 1868, exhibited reduced distribution. B. trevelyani longitudinal distribution was less than 25 km along the river continuum, with sporadic presence in the sandy foothills. S. bainsii was not found in the Lowland Zone, while previously this species extended from the mountainous zone to the confluence of the Tyhume and Keiskamma Rivers in the Lowland Zone. These indices supported the homogenization theory, as reflected by increased dissimilarity for two indigenous fish species, S. bainsii and B. trevelyani, among study sites. S. bainsii was previously distributed from source to confluence, while B. trevelyani recorded a 50percent decline at the study site below the Binfield Park Dam. To assign economic value to ecosystem services and assess post Rio-institutional parameters two hypothetical scenarios were developed from the ecological survey; one depicting current conditions and another depicting improved ecosystem services. Using a structured interview questionnaire, five ecosystem services in need of restoration were described to respondents. Applying the contingent valuation method respondents were asked a dichotomous choice question on willingness to pay (WTP). Results of the economic study from 209 personal interviews revealed, individuals were willing to pay an additional R 32.00 on their monthly water bill or R 384.00 annually. Generalizing this to 2 829 households living in the Alice and Ntselamanzi urban areas, a total value of R 1 086 336 would be realized annually. This was equivalent to the Nkonkobe Municipality annual budget for storm water management in Alice urban area. Costs/benefits revealed a positive net present value (NPV) = 1, which, in line with economic theory, meant gainers were able to compensate losers The institutional part of the economic survey sought to determine the effects of post Rio Earth Summit institutional measures on sustainable management of Tyhume River fish assemblage. A desk review of Rio Declaration and three South African statutes were used namely; Constitution Act 108 of 1996 (South African Constitution 1996); the National Environmental Management Biodiversity Act No. 10 of 2004 (NEMBA 2004), the National Environmental Management Act (NEMA) No. 107 of 1998 (NEMA 1998), and the National Water Act No. 36 of 1998 (NWA 1998). The Institutional and Analytic Development (IAD) Framework, coupled with requirements for sustainability of Multiple Use Resource Domains were used for the analysis. De Jure, the statutes had internationalization of environmental costs through “polluter pays principle”, while sustainable use was the overarching goal. De facto, the community participation, a requisite of post Rio measures, was low; however 89percent of community respondents were willing to join an environmental conservation group. This, coupled with the fact that 77percent of those interviewed supported the establishment of a Tyhume River Restoration Fund, provided scope for a broad based community participation framework This study contributes to sustainable use of Tyhume River and other lotic systems by generating information on the link between anthropogenic effects on fish biodiversity, economic value of ecosystems services and institutional mechanisms.
- Full Text:
- Date Issued: 2018
AP-MOVPE growth and characterisation of GaSb/GaAs quantum dots
- Authors: Tile, Ngcali
- Date: 2018
- Subjects: Quantum theory , Quantum electronics Quantum dots Semiconductors
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/36716 , vital:34047
- Description: GaSb/GaAs quantum dots (QD) were grown by atmospheric pressure (AP) metal-organic vapour phase epitaxy (MOVPE) using triethylgallium (TEGa), tertiarybutylarsine (tBAs) and trimethylantimony (TMSb) as gallium (Ga), arsenic (As) and (Sb) sources, respectively. The effect of AP-MOVPE growth parameters on the formation of GaSb QD structures on GaAs was studied. The formation of small, coherent GaSb dots on GaAs improved with decreasing V/III ratios, which were controlled through changing either the TMSb/TEGa ratio at a constant growth temperature or changing the growth temperature at a constant TMSb/TEGa ratio. The maximum effective V/III ratio for dot formation was 0.175. The dot density was more sensitive to growth time than to source mole fraction in the reactor, since time determines the amount of deposited material. The dot density increased with increasing growth time, while the shape and size of the dots were more sensitive to the source vapour mole fraction, which controls the growth rate. Lower mole fractions resulted in smaller sized dots with a more uniform distribution compared to higher mole fractions. Dome-shaped dots with densities as high as 4×1010 cm-2, average base length of 35 nm and average height of 5 nm were achieved. Capping of GaSb QDs at high temperatures caused flattening and the formation of a thin, inhomogeneous GaSb layer inside GaAs. No obvious QD photoluminescence (PL) peak was detected for these samples. A two stage process for capping the dots (involving growth of a low temperature GaAs cap, followed by a high temperature cap) led to the retention of the dot-like features in/on a wetting layer (WL) of GaSb and distinct PL peaks for both the QDs and WL. An increase in excitation power during PL measurements for this particular sample caused the QD and WL peaks to shift to higher energies. This is attributed to electrostatic band bending, leading to triangular potential wells, typical for type II band alignment between GaAs and strained GaSb. Variable temperature PL measurements showed the decrease in the intensity of the WL peak to be faster than that of the QD peak as the measurement temperature increased. A detailed high resolution transmission electron microscopy analysis was performed to study the morphology and chemical interaction between GaAs and GaSb regions for capped GaSb/GaAs QDs. The capped dots had dimensions similar to those of uncapped dots and had a higher concentration of Sb at their center, with the periphery being intermixed with GaAs. Measurement of lattice strain performed inside these dots revealed the strain to be distributed inhomogenously throughout the dot area. The effect of GaAs host matrix on excitonic behaviour in AP-MOVPE grown GaSb/GaAs quantum dots was investigated. Room temperature (RT) PL emission was achieved from a single layer of quantum dots by controlling the GaAs host matrix growth temperature. These samples were prepared using a GaSb dot growth temperature of 530 °C, followed by growth of a thin GaAs ‘cold’ cap, before depositing the final part of the GaAs capping layer at either 550 °C, 600 °C or 650 °C. PL measurements at 10 K revealed QD emission peaks for all the samples at around 1.1 eV. However, variable temperature PL revealed different thermal quenching rates of the emission, with the rates of quenching reduced with increasing GaAs growth temperature. This was ascribed to reduced defect densities in GaAs grown at higher temperature, which resulted in QD emission even at RT. This RT emission peaked at approximately 1 eV. The hole localisation energy determined for these samples at RT was approximately 470 meV.
- Full Text:
- Date Issued: 2018
- Authors: Tile, Ngcali
- Date: 2018
- Subjects: Quantum theory , Quantum electronics Quantum dots Semiconductors
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/36716 , vital:34047
- Description: GaSb/GaAs quantum dots (QD) were grown by atmospheric pressure (AP) metal-organic vapour phase epitaxy (MOVPE) using triethylgallium (TEGa), tertiarybutylarsine (tBAs) and trimethylantimony (TMSb) as gallium (Ga), arsenic (As) and (Sb) sources, respectively. The effect of AP-MOVPE growth parameters on the formation of GaSb QD structures on GaAs was studied. The formation of small, coherent GaSb dots on GaAs improved with decreasing V/III ratios, which were controlled through changing either the TMSb/TEGa ratio at a constant growth temperature or changing the growth temperature at a constant TMSb/TEGa ratio. The maximum effective V/III ratio for dot formation was 0.175. The dot density was more sensitive to growth time than to source mole fraction in the reactor, since time determines the amount of deposited material. The dot density increased with increasing growth time, while the shape and size of the dots were more sensitive to the source vapour mole fraction, which controls the growth rate. Lower mole fractions resulted in smaller sized dots with a more uniform distribution compared to higher mole fractions. Dome-shaped dots with densities as high as 4×1010 cm-2, average base length of 35 nm and average height of 5 nm were achieved. Capping of GaSb QDs at high temperatures caused flattening and the formation of a thin, inhomogeneous GaSb layer inside GaAs. No obvious QD photoluminescence (PL) peak was detected for these samples. A two stage process for capping the dots (involving growth of a low temperature GaAs cap, followed by a high temperature cap) led to the retention of the dot-like features in/on a wetting layer (WL) of GaSb and distinct PL peaks for both the QDs and WL. An increase in excitation power during PL measurements for this particular sample caused the QD and WL peaks to shift to higher energies. This is attributed to electrostatic band bending, leading to triangular potential wells, typical for type II band alignment between GaAs and strained GaSb. Variable temperature PL measurements showed the decrease in the intensity of the WL peak to be faster than that of the QD peak as the measurement temperature increased. A detailed high resolution transmission electron microscopy analysis was performed to study the morphology and chemical interaction between GaAs and GaSb regions for capped GaSb/GaAs QDs. The capped dots had dimensions similar to those of uncapped dots and had a higher concentration of Sb at their center, with the periphery being intermixed with GaAs. Measurement of lattice strain performed inside these dots revealed the strain to be distributed inhomogenously throughout the dot area. The effect of GaAs host matrix on excitonic behaviour in AP-MOVPE grown GaSb/GaAs quantum dots was investigated. Room temperature (RT) PL emission was achieved from a single layer of quantum dots by controlling the GaAs host matrix growth temperature. These samples were prepared using a GaSb dot growth temperature of 530 °C, followed by growth of a thin GaAs ‘cold’ cap, before depositing the final part of the GaAs capping layer at either 550 °C, 600 °C or 650 °C. PL measurements at 10 K revealed QD emission peaks for all the samples at around 1.1 eV. However, variable temperature PL revealed different thermal quenching rates of the emission, with the rates of quenching reduced with increasing GaAs growth temperature. This was ascribed to reduced defect densities in GaAs grown at higher temperature, which resulted in QD emission even at RT. This RT emission peaked at approximately 1 eV. The hole localisation energy determined for these samples at RT was approximately 470 meV.
- Full Text:
- Date Issued: 2018
Application of a quality by design approach to optimise an existing product
- Authors: Maxwell, Taryn Lee
- Date: 2018
- Subjects: Pharmaceutical chemistry , Drugs -- Design Pharmaceutical technology
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10948/32752 , vital:32341
- Description: Quality by design is a science and risk based approach whereby quality is built into the product or process during the pharmaceutical development. although quality by design is encouraged for pharmaceutical development. it is possible to apply quality by design to optimize an existing product as part of a continual improvement strategy. the purpose of this study is to determine which factors should be considered to justify the application of quality by design to optimize an existing product.
- Full Text: false
- Date Issued: 2018
- Authors: Maxwell, Taryn Lee
- Date: 2018
- Subjects: Pharmaceutical chemistry , Drugs -- Design Pharmaceutical technology
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10948/32752 , vital:32341
- Description: Quality by design is a science and risk based approach whereby quality is built into the product or process during the pharmaceutical development. although quality by design is encouraged for pharmaceutical development. it is possible to apply quality by design to optimize an existing product as part of a continual improvement strategy. the purpose of this study is to determine which factors should be considered to justify the application of quality by design to optimize an existing product.
- Full Text: false
- Date Issued: 2018
Application of health belief model in developing contextual guidelines for adherence to antiretroviral treatment among adolescents and youths in Buffalo City Metropolitan Municipality District, East London, South Africa
- Authors: Mayeye, Bulelwa
- Date: 2018
- Subjects: HIV-positive children--Treatment--Management AIDS (Disease) in adolescence HIV-positive youth
- Language: English
- Type: Thesis , Doctoral , Nursing
- Identifier: http://hdl.handle.net/10353/15572 , vital:40472
- Description: Background: Adhering to the treatment instructions for a long-term illness poses a great challenge to the client especially adolescents and youths. In public health centers it is observed that most adolescents and youths on Ante Retroviral Treatment (ART) do not continue taking ART and do not honor their Art related scheduled appointments at the clinic. An increase loss to follow up among these cohorts is noticeable in Buffalo City Metropolitan Municipality district. Inconsistent adherence to ART may result in the development of resistance mutations. Purpose: The purpose of the study was to develop and describe context – specific antiretroviral treatment guidelines based on the biomedical, cognitive and psychosocial needs of the adolescents and youths at the Buffalo City Metropolitan Municipality district. Methodology: The study was conducted in two phases, phase one consisted of quantitative and qualitative approaches. For phase one an explanatory sequential mixed method of quantitative and qualitative designs was employed. The study was guided by Health Belief Model. The target population were adolescents and youths receiving ART from the selected health facilities in Buffalo City Metropolitan Municipality District in the Province of the Eastern Cape. Participants were chosen based on purposive sampling. A convenience sample of 206 adolescents and youths between the ages of 14 to 24 attending ARV clinics were approached. Ethical considerations, that is, the rights of all the participants were honoured. Data was collected using self administered questionnaires followed by semi-structured interview where face to face interviews were conducted. Reliability validity and trustworthiness of the research was ensured. Quantitative data was analysed through descriptive statistics. For qualitative approach transcrips were coded thematically. In Phase 2, context – specific antiretroviral treatment guidelines were developed to promote adherence to ART by adolescents and youths of Buffalo City Metropolitan Municipality district. Results: About 35percent of the participants indicated low adherence, 31percent for moderate adherence and 34percent for high adherence. A strong correlation between interpersonal relationship and adherence (p = 0.008), a correlation between aspect of care related to clinic and adherence (p = 0.028), a significant correlation between social support and adherence to ART (p = 0.006) and a significant relationship between self- efficacy and adherence to ART (p = 0.000) were obtained. No correlation between demographic status and adherence except for race. Results from the interviews revealed that barriers to adherence were more evident than enabling factors. Recommendations: Health service providers should strengthen ART adherence programmes for adolescents and youths by applying principles as they appear in the context – based guidelines.
- Full Text:
- Date Issued: 2018
- Authors: Mayeye, Bulelwa
- Date: 2018
- Subjects: HIV-positive children--Treatment--Management AIDS (Disease) in adolescence HIV-positive youth
- Language: English
- Type: Thesis , Doctoral , Nursing
- Identifier: http://hdl.handle.net/10353/15572 , vital:40472
- Description: Background: Adhering to the treatment instructions for a long-term illness poses a great challenge to the client especially adolescents and youths. In public health centers it is observed that most adolescents and youths on Ante Retroviral Treatment (ART) do not continue taking ART and do not honor their Art related scheduled appointments at the clinic. An increase loss to follow up among these cohorts is noticeable in Buffalo City Metropolitan Municipality district. Inconsistent adherence to ART may result in the development of resistance mutations. Purpose: The purpose of the study was to develop and describe context – specific antiretroviral treatment guidelines based on the biomedical, cognitive and psychosocial needs of the adolescents and youths at the Buffalo City Metropolitan Municipality district. Methodology: The study was conducted in two phases, phase one consisted of quantitative and qualitative approaches. For phase one an explanatory sequential mixed method of quantitative and qualitative designs was employed. The study was guided by Health Belief Model. The target population were adolescents and youths receiving ART from the selected health facilities in Buffalo City Metropolitan Municipality District in the Province of the Eastern Cape. Participants were chosen based on purposive sampling. A convenience sample of 206 adolescents and youths between the ages of 14 to 24 attending ARV clinics were approached. Ethical considerations, that is, the rights of all the participants were honoured. Data was collected using self administered questionnaires followed by semi-structured interview where face to face interviews were conducted. Reliability validity and trustworthiness of the research was ensured. Quantitative data was analysed through descriptive statistics. For qualitative approach transcrips were coded thematically. In Phase 2, context – specific antiretroviral treatment guidelines were developed to promote adherence to ART by adolescents and youths of Buffalo City Metropolitan Municipality district. Results: About 35percent of the participants indicated low adherence, 31percent for moderate adherence and 34percent for high adherence. A strong correlation between interpersonal relationship and adherence (p = 0.008), a correlation between aspect of care related to clinic and adherence (p = 0.028), a significant correlation between social support and adherence to ART (p = 0.006) and a significant relationship between self- efficacy and adherence to ART (p = 0.000) were obtained. No correlation between demographic status and adherence except for race. Results from the interviews revealed that barriers to adherence were more evident than enabling factors. Recommendations: Health service providers should strengthen ART adherence programmes for adolescents and youths by applying principles as they appear in the context – based guidelines.
- Full Text:
- Date Issued: 2018
Application of hidden Markov models and their extensions to animal movement data
- Authors: Van Niekerk, Bracken
- Date: 2018
- Subjects: Markov processes Animal locomotion Time-series analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23835 , vital:30624
- Description: Hidden Markov Models (HMMs) have become increasingly popular in animal movement studies as they provide a flexible modelling approach and take the correlation between successive observations into account. They can segment the movement paths into latent states, which can be considered as rough proxies for the behaviours of the animals. This study comprises of two sections, both involving the application of HMMs to large terrestrial mammal movement data. Usually step lengths representing the displacement distances between successive observations, turning angles measuring the tortuosity, or a bivariate input of both variables are used as inputs in the models. It has been found in the literature that the turning angle is either included in the modelling process or it is excluded without much justification for doing so. The first part of this study investigates the nfluence of the turning angle on the model output and resultant interpretations of the HMMs when modelling the trajectories of large terrestrial mammals in southern Africa. Results revealed at different time scales, and for both predator and herbivore species in this study, that the turning angle does not influence the state allocation of the HMMs, which is the main output in terms of interpreting the behaviours of the animals. It is thought in most cases that the inclusion of the turning angle overcomplicates the models unnecessarily without contributing any additional information in terms of the behavioural interpretations or improving the overall fit of the models. This was found for the variety of movements of the species under observation in this study. The second part of this study attempts to validate the state allocation of the HMMs fitted to eland trajectories in the Greater Addo Elephant National Park in the Eastern Cape, with the use of camera trap data. This presented a unique opportunity as this type of data is mainly used for abundance or capture-recapture studies, and the HMMs are rarely validated as the true behaviours of the animals are seldom known. Results revealed that the same diel patterns were detected by the HMMs that were shown by the classified camera trap data. Direct comparisons of the observations where the dates and times matched for the telemetry and camera trap data could be done in several rare instances, which revealed many similarities. Although it was not an ideal comparison, the camera trap data provided a rough validation of the state allocation of the HMMs used in the study.
- Full Text:
- Date Issued: 2018
- Authors: Van Niekerk, Bracken
- Date: 2018
- Subjects: Markov processes Animal locomotion Time-series analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23835 , vital:30624
- Description: Hidden Markov Models (HMMs) have become increasingly popular in animal movement studies as they provide a flexible modelling approach and take the correlation between successive observations into account. They can segment the movement paths into latent states, which can be considered as rough proxies for the behaviours of the animals. This study comprises of two sections, both involving the application of HMMs to large terrestrial mammal movement data. Usually step lengths representing the displacement distances between successive observations, turning angles measuring the tortuosity, or a bivariate input of both variables are used as inputs in the models. It has been found in the literature that the turning angle is either included in the modelling process or it is excluded without much justification for doing so. The first part of this study investigates the nfluence of the turning angle on the model output and resultant interpretations of the HMMs when modelling the trajectories of large terrestrial mammals in southern Africa. Results revealed at different time scales, and for both predator and herbivore species in this study, that the turning angle does not influence the state allocation of the HMMs, which is the main output in terms of interpreting the behaviours of the animals. It is thought in most cases that the inclusion of the turning angle overcomplicates the models unnecessarily without contributing any additional information in terms of the behavioural interpretations or improving the overall fit of the models. This was found for the variety of movements of the species under observation in this study. The second part of this study attempts to validate the state allocation of the HMMs fitted to eland trajectories in the Greater Addo Elephant National Park in the Eastern Cape, with the use of camera trap data. This presented a unique opportunity as this type of data is mainly used for abundance or capture-recapture studies, and the HMMs are rarely validated as the true behaviours of the animals are seldom known. Results revealed that the same diel patterns were detected by the HMMs that were shown by the classified camera trap data. Direct comparisons of the observations where the dates and times matched for the telemetry and camera trap data could be done in several rare instances, which revealed many similarities. Although it was not an ideal comparison, the camera trap data provided a rough validation of the state allocation of the HMMs used in the study.
- Full Text:
- Date Issued: 2018
Appraisal of wastewater final effluents and river water as reservoirs of cholera and non-cholera causing vibrio species : case study of the Amatole and OR Tambo District Municipalities
- Authors: Nontongana, Nolonwabo
- Date: 2018
- Subjects: Vibrio -- South Africa -- Eastern Cape Vibrio cholerae Disease Reservoirs
- Language: English
- Type: Thesis , Doctoral , Microbiology
- Identifier: http://hdl.handle.net/10353/9929 , vital:35146
- Description: Vibrio infections remain a serious threat to public health. In the last decade, Vibrio disease outbreaks have created a painful awareness of the personal, economic, societal, and public health costs associated with the impact of inadequately treated wastewater effluents. This study was therefore designed to assess the occurrence of cholera and non-cholera causing Vibrio species in the final effluents of wastewater treatment plants and river waters in the Amatole (BT WWTP) and OR Tambo District municipalities (MT WWTP and QN River) of the Eastern Cape Province. Samples were collected monthly from December 2016 to November 2017 from the final effluent, 500 meters upstream and downstream of the discharge points and analysed for physicochemical parameters, Vibrio pathogens prevalence and their antibiogram characteristics using both culture-based and molecular techniques. Samples were collected aseptically using sterile 1L glass bottles containing 0.5 ml of sterile sodium thiosulphate solution and transported on ice to the laboratory for analyses within 6hrs of collection. The membrane filtration method was used for enumeration of presumptive Vibrio densities on thiosulfate citrate bile salt (TCBS) agar plates. Polymerase chain reaction (PCR) was then used to confirm the identities of the presumptive Vibrio species using the species-specific primers. The confirmed isolates were further subjected to molecular characterization to confirm their respective pathotypes. Antimicrobial susceptibility testing was done by the standard disc diffusion method recommended by the Clinical and Laboratory Standards Institute. The recovered Vibrio species were tested against a panel of 17 antibiotics. Physicochemical parameters measured include pH, temperature, electrical conductivity, salinity, turbidity, total dissolved solid (TDS), dissolved oxygen (DO), biochemical oxygen demand (BOD) and chlorine (only for BT WWTP). Unacceptably high levels of the assayed parameters were observed in many cases for TDS (66 - 879 mg/l), turbidity (2.0 -722.33 NTU) and DO (2.5 – 9.7 mg/l) as well as chlorine (0.2 – 3.2 mg/L). Presumptive Vibrio densities varied from 2.91 to 3.91 log10 CFU/100 ml and 2.67 to 3.18 log CFU/100ml, for BT WWTP and MT WWTP respectively. The densities for the QN River ranged between 2.51 to 3.99 log10 CFU/100mL. Out of 720 presumptive isolates recovered, 619 (86 percent) were found to be positive for the Vibrio genus. Molecular confirmation of the presumptive Vibrio species revealed the presence of V. fluvialis (16), V. vulnificus (12), V aliginolyticus (9), V. parahaemolyticus (37) and V. cholerae (5) isolates were confirmed. The susceptibility against 17 different antibiotics by the recovered species were examined. V. cholerae was notably resistant against nalidixic acid (3) and Ampicilin (2), all the V. vulnificus isolates were resistant against ampicillin (16), V. fluvialis showed resistance against ciprofloxacin and nalidixic acid, all (9) isolates for V. alginolyticus were resistant against ampicillin. V. parahaemolyticus showed resistance against cefutoxime (16), cefuxime (8) and ampicillin (13). The recovery of Vibrio in the discharged effluents throughout the sampling period even in adequately disinfected effluents is not acceptable considering that Vibrio are pathogenic bacteria. The findings of this study underline the need for constant monitoring of the physicochemical and microbiological qualities of discharged effluents and might also be suggestive for a review of the disinfection methods used at the treatment works as this might pose adverse health risk to the communities which still rely heavily on these surface waters.
- Full Text:
- Date Issued: 2018
- Authors: Nontongana, Nolonwabo
- Date: 2018
- Subjects: Vibrio -- South Africa -- Eastern Cape Vibrio cholerae Disease Reservoirs
- Language: English
- Type: Thesis , Doctoral , Microbiology
- Identifier: http://hdl.handle.net/10353/9929 , vital:35146
- Description: Vibrio infections remain a serious threat to public health. In the last decade, Vibrio disease outbreaks have created a painful awareness of the personal, economic, societal, and public health costs associated with the impact of inadequately treated wastewater effluents. This study was therefore designed to assess the occurrence of cholera and non-cholera causing Vibrio species in the final effluents of wastewater treatment plants and river waters in the Amatole (BT WWTP) and OR Tambo District municipalities (MT WWTP and QN River) of the Eastern Cape Province. Samples were collected monthly from December 2016 to November 2017 from the final effluent, 500 meters upstream and downstream of the discharge points and analysed for physicochemical parameters, Vibrio pathogens prevalence and their antibiogram characteristics using both culture-based and molecular techniques. Samples were collected aseptically using sterile 1L glass bottles containing 0.5 ml of sterile sodium thiosulphate solution and transported on ice to the laboratory for analyses within 6hrs of collection. The membrane filtration method was used for enumeration of presumptive Vibrio densities on thiosulfate citrate bile salt (TCBS) agar plates. Polymerase chain reaction (PCR) was then used to confirm the identities of the presumptive Vibrio species using the species-specific primers. The confirmed isolates were further subjected to molecular characterization to confirm their respective pathotypes. Antimicrobial susceptibility testing was done by the standard disc diffusion method recommended by the Clinical and Laboratory Standards Institute. The recovered Vibrio species were tested against a panel of 17 antibiotics. Physicochemical parameters measured include pH, temperature, electrical conductivity, salinity, turbidity, total dissolved solid (TDS), dissolved oxygen (DO), biochemical oxygen demand (BOD) and chlorine (only for BT WWTP). Unacceptably high levels of the assayed parameters were observed in many cases for TDS (66 - 879 mg/l), turbidity (2.0 -722.33 NTU) and DO (2.5 – 9.7 mg/l) as well as chlorine (0.2 – 3.2 mg/L). Presumptive Vibrio densities varied from 2.91 to 3.91 log10 CFU/100 ml and 2.67 to 3.18 log CFU/100ml, for BT WWTP and MT WWTP respectively. The densities for the QN River ranged between 2.51 to 3.99 log10 CFU/100mL. Out of 720 presumptive isolates recovered, 619 (86 percent) were found to be positive for the Vibrio genus. Molecular confirmation of the presumptive Vibrio species revealed the presence of V. fluvialis (16), V. vulnificus (12), V aliginolyticus (9), V. parahaemolyticus (37) and V. cholerae (5) isolates were confirmed. The susceptibility against 17 different antibiotics by the recovered species were examined. V. cholerae was notably resistant against nalidixic acid (3) and Ampicilin (2), all the V. vulnificus isolates were resistant against ampicillin (16), V. fluvialis showed resistance against ciprofloxacin and nalidixic acid, all (9) isolates for V. alginolyticus were resistant against ampicillin. V. parahaemolyticus showed resistance against cefutoxime (16), cefuxime (8) and ampicillin (13). The recovery of Vibrio in the discharged effluents throughout the sampling period even in adequately disinfected effluents is not acceptable considering that Vibrio are pathogenic bacteria. The findings of this study underline the need for constant monitoring of the physicochemical and microbiological qualities of discharged effluents and might also be suggestive for a review of the disinfection methods used at the treatment works as this might pose adverse health risk to the communities which still rely heavily on these surface waters.
- Full Text:
- Date Issued: 2018
Approaches to detecting and assessing patterns, processes and responses to change in South African estuaries
- Authors: Van Niekerk, Lara
- Date: 2018
- Subjects: Estuaries -- South Africa , Climatic changes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10948/45491 , vital:38621
- Description: The research presented indicates deep knowledge of estuary pattern-process-function across a broad range of estuary types. This study successfully developed and applied approaches to detect change at varying temporal and spatial scales in South African estuaries. This assessment was based on the physical characteristics of estuaries and predicted or measured change in the drivers of estuary health. This is the first study in the country to review and synthesise the vulnerability of South African estuaries to Climate Change on a regional scale. Through sound scientific approaches this research has advanced our knowledge on complex estuarine systems and made a significant contribution globally to approaches for the conservation and management of estuaries.
- Full Text:
- Date Issued: 2018
- Authors: Van Niekerk, Lara
- Date: 2018
- Subjects: Estuaries -- South Africa , Climatic changes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10948/45491 , vital:38621
- Description: The research presented indicates deep knowledge of estuary pattern-process-function across a broad range of estuary types. This study successfully developed and applied approaches to detect change at varying temporal and spatial scales in South African estuaries. This assessment was based on the physical characteristics of estuaries and predicted or measured change in the drivers of estuary health. This is the first study in the country to review and synthesise the vulnerability of South African estuaries to Climate Change on a regional scale. Through sound scientific approaches this research has advanced our knowledge on complex estuarine systems and made a significant contribution globally to approaches for the conservation and management of estuaries.
- Full Text:
- Date Issued: 2018
Aquatic habitat shift assessment in a groundwater-fed semi-arid stream: an investigation into the response of Karoo hydroecology to system variability
- Authors: Ellis, Natalie
- Date: 2018
- Subjects: Aquatic habitats -- South Africa -- Karoo , Arid regions -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo , Stream ecology -- South Africa -- Karoo
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61882 , vital:28072
- Description: From introduction: The subject of biological response to changes in aquatic habitat is one which has been well explored in many regions of the world. Examples include work in south east Spain by Mellado Diaz et al. (2008) and Oliva-Paterna et al. (2003), in western United States of America by Hauer and Lorang (2004), and in West Germany by Meyer et al. (2003). Similarly, a number of studies have been conducted in semi-arid regions, exploring elements such as erosion, climate, lithology and landscape formations (e.g. Boardman et al., 2013; Le Maitre et al., 2007; Meyer et al., 2003). However, apart from the study by Uys (1997), and Uys and O’Keeffe (1997), there is a noticeable lack of literature on aquatic habitat shifts in semi-arid stream systems, despite these systems being recognised for their high natural variability. This study provides a base-level approach to conducting habitat shift assessments in a semi-arid stream system and monitoring the hydroecological responses to system variability.
- Full Text:
- Date Issued: 2018
- Authors: Ellis, Natalie
- Date: 2018
- Subjects: Aquatic habitats -- South Africa -- Karoo , Arid regions -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo , Stream ecology -- South Africa -- Karoo
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61882 , vital:28072
- Description: From introduction: The subject of biological response to changes in aquatic habitat is one which has been well explored in many regions of the world. Examples include work in south east Spain by Mellado Diaz et al. (2008) and Oliva-Paterna et al. (2003), in western United States of America by Hauer and Lorang (2004), and in West Germany by Meyer et al. (2003). Similarly, a number of studies have been conducted in semi-arid regions, exploring elements such as erosion, climate, lithology and landscape formations (e.g. Boardman et al., 2013; Le Maitre et al., 2007; Meyer et al., 2003). However, apart from the study by Uys (1997), and Uys and O’Keeffe (1997), there is a noticeable lack of literature on aquatic habitat shifts in semi-arid stream systems, despite these systems being recognised for their high natural variability. This study provides a base-level approach to conducting habitat shift assessments in a semi-arid stream system and monitoring the hydroecological responses to system variability.
- Full Text:
- Date Issued: 2018
Archie Mafeje and the question of philosophy as a liberatory discourse
- Authors: Dladla, Thabang
- Date: 2018
- Subjects: Philosophy, African Eurocentrism Liberty
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10353/12160 , vital:39192
- Description: This dissertation seeks to articulate a liberatory conception of philosophy which interprets reality on its own terms. It is an attempt to intervene in the practice of philosophy in South Africa, which has continued along colonial lines expressed through the marginality of African philosophy up to the present, to the general neglect of the unjust and divisive social reality that defines South Africa. It is our argument that such a continuity is indicative of outstanding liberation on the part of the indigenous people conquered in the unjust wars of colonisation. Our main task then is to struggle for this liberation at the epistemic level with Archie Mafeje, through an examination of his intellectual works and life as a revolutionary intellectual, as an inspiration and an instance of a liberatory practice of philosophy. We draw on the work of Archie Mafeje to elaborate and defend his account of African Philosophy, as a historically specific expression of the liberatory struggle of Africans against unjust Euro-centric colonial domination. This shall be achieved in three instances. In the first instance, Chapter 1, we trace the history of institutionalised philosophy in South Africa outlining Eurocentrism and mimesis as its defining features. In the second instance, Chapter 2, a history of contemporary African philosophy is outlined as emanative from the question concerning the existence of African philosophy, of which mainstream South African philosophy has largely been ignorant. In the final instance, Chapter 3 and 4, a liberatory practice of philosophy is presented, as a necessary response to this context, with Mafeje’s account of African philosophy defended as such an instance. The birth of the Azanian Philosophical Society is also presented as such an instance and as a challenge to the unchallenged hegemony of white philosophy in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Dladla, Thabang
- Date: 2018
- Subjects: Philosophy, African Eurocentrism Liberty
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10353/12160 , vital:39192
- Description: This dissertation seeks to articulate a liberatory conception of philosophy which interprets reality on its own terms. It is an attempt to intervene in the practice of philosophy in South Africa, which has continued along colonial lines expressed through the marginality of African philosophy up to the present, to the general neglect of the unjust and divisive social reality that defines South Africa. It is our argument that such a continuity is indicative of outstanding liberation on the part of the indigenous people conquered in the unjust wars of colonisation. Our main task then is to struggle for this liberation at the epistemic level with Archie Mafeje, through an examination of his intellectual works and life as a revolutionary intellectual, as an inspiration and an instance of a liberatory practice of philosophy. We draw on the work of Archie Mafeje to elaborate and defend his account of African Philosophy, as a historically specific expression of the liberatory struggle of Africans against unjust Euro-centric colonial domination. This shall be achieved in three instances. In the first instance, Chapter 1, we trace the history of institutionalised philosophy in South Africa outlining Eurocentrism and mimesis as its defining features. In the second instance, Chapter 2, a history of contemporary African philosophy is outlined as emanative from the question concerning the existence of African philosophy, of which mainstream South African philosophy has largely been ignorant. In the final instance, Chapter 3 and 4, a liberatory practice of philosophy is presented, as a necessary response to this context, with Mafeje’s account of African philosophy defended as such an instance. The birth of the Azanian Philosophical Society is also presented as such an instance and as a challenge to the unchallenged hegemony of white philosophy in South Africa.
- Full Text:
- Date Issued: 2018
Artisanal mining and its contribution to sustainable rural livelihoods : a case of Esigodini area, Umzingwane rural district, Matabeleland South Province of Zimbabwe
- Authors: Nkala, Khayelihle
- Date: 2018
- Subjects: Mineral industries Rural poor Sustainable development
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10353/15551 , vital:40458
- Description: This study examined the contribution of artisanal mining to the livelihoods of rural communities. Artisanal mining has over the past decade been taken up by rural communities as an alternative of sustaining their livelihoods due to the collapse of agriculture due to the successive droughts, economic meltdown and the general failure of the fast track land reform program. Hence this study sought to fill this knowledge gap using Esigodini as a case. The study made use of focus group discussions, interviews and documents review to gather information on how artisanal mining activities have contributed to the livelihoods of rural communities. Although artisanal mining has its negative impacts to the environment it does contribute to the livelihoods of communities, as the findings of the study reveal that the Esigodini community has benefited from improved socio-economic activities as a result of the practice.
- Full Text:
- Date Issued: 2018
- Authors: Nkala, Khayelihle
- Date: 2018
- Subjects: Mineral industries Rural poor Sustainable development
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10353/15551 , vital:40458
- Description: This study examined the contribution of artisanal mining to the livelihoods of rural communities. Artisanal mining has over the past decade been taken up by rural communities as an alternative of sustaining their livelihoods due to the collapse of agriculture due to the successive droughts, economic meltdown and the general failure of the fast track land reform program. Hence this study sought to fill this knowledge gap using Esigodini as a case. The study made use of focus group discussions, interviews and documents review to gather information on how artisanal mining activities have contributed to the livelihoods of rural communities. Although artisanal mining has its negative impacts to the environment it does contribute to the livelihoods of communities, as the findings of the study reveal that the Esigodini community has benefited from improved socio-economic activities as a result of the practice.
- Full Text:
- Date Issued: 2018
Aspects Allocentristes de l’Humanisme dans l’Univers Romanesque de Williams Sassine
- Authors: Dami, Emmanuel Naancin
- Date: 2018
- Subjects: Sassine, Williams, 1944-1997 -- Criticism and interpretation , Guinean fiction (French) -- 20th century -- History and criticism , Humanism in literature , Human beings in literature , Postcolonialism in literature , Existentialism in literature
- Language: French , English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/61957 , vital:28089
- Description: The human being, his behaviour and more importantly, his very essence have, for time immemorial, proven to be enigmatic to many a man and to researchers in particular. Consequently, the need for a thorough and more profound understanding of man has made him the epicentre of epistemic investigations across many academic disciplines. This, unfortunately, does not seem to have shaded bright lights on the grey areas bordering on his nature to his behavior. This, in turn, opens up other windows requiring further probes. For instance, proponents of the Neo-classical economic school contend that the human being is homo oeconomicus. This implies that man is intrinsically egocentric and a rational being whose decisions are based on informed choices driven by his urge for maximal utility geared towards his personal satisfaction (O’Boyle 2009; Caruso 2012). This stance invalidates man’s ability to do ‘disinterested good’ in any form. African francophone literature is replete with different and diverse images of man, his behaviour and existential conditions: sufferings and struggles. It, therefore, constitutes, inter alia, a laboratory in which researchers undertake investigative endeavours. This thesis beams its floodlights on the allocentric aspects of humanism in the novels of Williams Sassine. Thus, using the phenomenological and ‘clavieniste’ lenses as overarching operational theories, the thesis investigates Sassine’s novels with the view to shading a ray of light on the ‘humanistic man’ especially the allocentric dimensions of his nature and comportment. Emphasis is laid on the motives and motivations underlying the individual and the in-group struggle of the sassinien heroes in the emancipation of their society from the shackles of colonial and postcolonial domination, exploitation and subjugation resulting in self-determination and the subsequent disenchantment. Furthermore, the thesis examines the nature and character of human charity, generosity and sacrifices among the characters in the novels. In conclusion, the thesis establishes, through an x-ray of the nature of actions and decisions of certain characters in the novels, the examination of the conscious and subconscious intentions underlying these same actions and decisions which, on a face value, are apparently altruistic, that the sassinien heroes’ efforts and sacrifices are geared towards the common and greater good. This invariably means that man is, indeed, capable of posing disinterested acts of charity and bringing succour, devoid of any ulterior motives for personal gain, to his fellow humans. The position of the Neo-classical economists is consequently over-assuming, sweeping and tad generalizing. The sassinien characters have demonstrated beyond reasonable doubt that they are humanists. Their nature, the remote and immediate causes of their fights, the goals and objectives of their struggles and their spirit of abnegation have indeed proven that “human beings have the right and the responsibility to give meaning and shape to their own lives. [They have stood] for the building of a more humane society through an ethics based on the human and other natural values in a spirit of reason and free inquiry through human capabilities” (AHA 2017 : 3).
- Full Text:
- Date Issued: 2018
- Authors: Dami, Emmanuel Naancin
- Date: 2018
- Subjects: Sassine, Williams, 1944-1997 -- Criticism and interpretation , Guinean fiction (French) -- 20th century -- History and criticism , Humanism in literature , Human beings in literature , Postcolonialism in literature , Existentialism in literature
- Language: French , English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/61957 , vital:28089
- Description: The human being, his behaviour and more importantly, his very essence have, for time immemorial, proven to be enigmatic to many a man and to researchers in particular. Consequently, the need for a thorough and more profound understanding of man has made him the epicentre of epistemic investigations across many academic disciplines. This, unfortunately, does not seem to have shaded bright lights on the grey areas bordering on his nature to his behavior. This, in turn, opens up other windows requiring further probes. For instance, proponents of the Neo-classical economic school contend that the human being is homo oeconomicus. This implies that man is intrinsically egocentric and a rational being whose decisions are based on informed choices driven by his urge for maximal utility geared towards his personal satisfaction (O’Boyle 2009; Caruso 2012). This stance invalidates man’s ability to do ‘disinterested good’ in any form. African francophone literature is replete with different and diverse images of man, his behaviour and existential conditions: sufferings and struggles. It, therefore, constitutes, inter alia, a laboratory in which researchers undertake investigative endeavours. This thesis beams its floodlights on the allocentric aspects of humanism in the novels of Williams Sassine. Thus, using the phenomenological and ‘clavieniste’ lenses as overarching operational theories, the thesis investigates Sassine’s novels with the view to shading a ray of light on the ‘humanistic man’ especially the allocentric dimensions of his nature and comportment. Emphasis is laid on the motives and motivations underlying the individual and the in-group struggle of the sassinien heroes in the emancipation of their society from the shackles of colonial and postcolonial domination, exploitation and subjugation resulting in self-determination and the subsequent disenchantment. Furthermore, the thesis examines the nature and character of human charity, generosity and sacrifices among the characters in the novels. In conclusion, the thesis establishes, through an x-ray of the nature of actions and decisions of certain characters in the novels, the examination of the conscious and subconscious intentions underlying these same actions and decisions which, on a face value, are apparently altruistic, that the sassinien heroes’ efforts and sacrifices are geared towards the common and greater good. This invariably means that man is, indeed, capable of posing disinterested acts of charity and bringing succour, devoid of any ulterior motives for personal gain, to his fellow humans. The position of the Neo-classical economists is consequently over-assuming, sweeping and tad generalizing. The sassinien characters have demonstrated beyond reasonable doubt that they are humanists. Their nature, the remote and immediate causes of their fights, the goals and objectives of their struggles and their spirit of abnegation have indeed proven that “human beings have the right and the responsibility to give meaning and shape to their own lives. [They have stood] for the building of a more humane society through an ethics based on the human and other natural values in a spirit of reason and free inquiry through human capabilities” (AHA 2017 : 3).
- Full Text:
- Date Issued: 2018
Aspects of the nutritional physiology of the perlemoen Haliotis midae (L.) and red abalone H. rufescens (Swainson)
- Authors: Kemp, Justin Oliver Gordon
- Date: 2018
- Subjects: Haliotis midae , Haliotis midae fisheries , Red abalone , Haliotis midae -- Feeding and feeds , Red abalone -- Feeding and feeds , Haliotis midae -- Nutrition -- Requirements , Red abalone -- Nutrition -- Requirements , Haliotis midae -- Metabolism , Red abalone -- Metabolism , Haliotis midae -- Physiology , Red abalone -- Physiology , Stable isotopes , Algae as feed
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62314 , vital:28154
- Description: The source of abalone for human consumption has shown a dramatic shift away from wild-capture fisheries in the last 30 years, with over 90% of global production now coming from aquaculture. Farmers initially relied on the natural food of abalone (macroalgae) as a culture feed, though in regions where macroalgae availability was limiting, the need to develop formulated feeds was evident. Extensive research effort has led to the development of a number of formulated feed products currently employed in the industry. These feeds, however, differ markedly from the mixed macroalgal diets that abalone have evolved to utilise, particularly in terms of protein content and carbohydrate structure. The degree to which the nutritional physiology of abalone responds to these novel formulated diets, with and without macroalgal supplementation, was investigated in the current study. A multifaceted approach, combining growth trials, stable isotope nutrient tracers and metabolic experiments, was employed to gain insight into the post-absorption dynamics and utilisation of dietary nutrients under varying dietary regimes of fresh macroalgae and formulated feed. Growth trials conducted with both Haliotis rufescens and H. midae showed significantly higher growth and protein utilisation efficiency for abalone fed macroalgal diets compared to formulated feeds. Furthermore, when formulated feeds were supplemented with macroalgae to form combination diets, growth and the utilization of protein was improved compared to the formulated-feed-only diet. The poor utilisation of protein by H. midae fed the formulated feed could be traced, using a method combining stable isotope bio-markers with a Bayesian mixing model (SIAR), to the low incorporation of the fishmeal component of protein in the diet. The marked postprandial drop in the O:N ratio on abalone fed formulated feeds indicate that the protein was being diverted into catabolic metabolic pathways. The metabolic cost of digestion, termed specific dynamic action (SDA), was negated as a factor in the improved growth of abalone fed macroalgal diets, with the SDA coefficient 2.1 times that observed for formulated feed. Furthermore, the postprandial haemolymph glucose concentration (HGC) in H. midae was elevated when fed formulated feed compared to macroalgae. The high levels of circulating glucose are likely a result of the structure the carbohydrate source in formulated feeds and stimulate the deposition of glycogen through the allosteric control of glycogen synthase. Formulated feeds produced higher cooked meat yields in canning simulation trials, suggesting that muscle glycogen content may indirectly play a role in increasing canning yields through the displacement of collagen. The results of these empirical studies are synthesised under key themes, discussed within the context of their potential commercial relevance and future research directions are highlighted.
- Full Text:
- Date Issued: 2018
- Authors: Kemp, Justin Oliver Gordon
- Date: 2018
- Subjects: Haliotis midae , Haliotis midae fisheries , Red abalone , Haliotis midae -- Feeding and feeds , Red abalone -- Feeding and feeds , Haliotis midae -- Nutrition -- Requirements , Red abalone -- Nutrition -- Requirements , Haliotis midae -- Metabolism , Red abalone -- Metabolism , Haliotis midae -- Physiology , Red abalone -- Physiology , Stable isotopes , Algae as feed
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62314 , vital:28154
- Description: The source of abalone for human consumption has shown a dramatic shift away from wild-capture fisheries in the last 30 years, with over 90% of global production now coming from aquaculture. Farmers initially relied on the natural food of abalone (macroalgae) as a culture feed, though in regions where macroalgae availability was limiting, the need to develop formulated feeds was evident. Extensive research effort has led to the development of a number of formulated feed products currently employed in the industry. These feeds, however, differ markedly from the mixed macroalgal diets that abalone have evolved to utilise, particularly in terms of protein content and carbohydrate structure. The degree to which the nutritional physiology of abalone responds to these novel formulated diets, with and without macroalgal supplementation, was investigated in the current study. A multifaceted approach, combining growth trials, stable isotope nutrient tracers and metabolic experiments, was employed to gain insight into the post-absorption dynamics and utilisation of dietary nutrients under varying dietary regimes of fresh macroalgae and formulated feed. Growth trials conducted with both Haliotis rufescens and H. midae showed significantly higher growth and protein utilisation efficiency for abalone fed macroalgal diets compared to formulated feeds. Furthermore, when formulated feeds were supplemented with macroalgae to form combination diets, growth and the utilization of protein was improved compared to the formulated-feed-only diet. The poor utilisation of protein by H. midae fed the formulated feed could be traced, using a method combining stable isotope bio-markers with a Bayesian mixing model (SIAR), to the low incorporation of the fishmeal component of protein in the diet. The marked postprandial drop in the O:N ratio on abalone fed formulated feeds indicate that the protein was being diverted into catabolic metabolic pathways. The metabolic cost of digestion, termed specific dynamic action (SDA), was negated as a factor in the improved growth of abalone fed macroalgal diets, with the SDA coefficient 2.1 times that observed for formulated feed. Furthermore, the postprandial haemolymph glucose concentration (HGC) in H. midae was elevated when fed formulated feed compared to macroalgae. The high levels of circulating glucose are likely a result of the structure the carbohydrate source in formulated feeds and stimulate the deposition of glycogen through the allosteric control of glycogen synthase. Formulated feeds produced higher cooked meat yields in canning simulation trials, suggesting that muscle glycogen content may indirectly play a role in increasing canning yields through the displacement of collagen. The results of these empirical studies are synthesised under key themes, discussed within the context of their potential commercial relevance and future research directions are highlighted.
- Full Text:
- Date Issued: 2018
Aspects of the population ecology, habitat use and behaviour of the endangered Knysna seahorse (Hippocampus capensis Boulenger, 1900) in a residential marina estate, Knysna, South Africa: implications for conservation
- Authors: Claassens, Louw
- Date: 2018
- Subjects: Endangered species -- South Africa -- Knysna , Sea horses -- Behavior -- South Africa -- Knysna , Sea horses -- Habitat -- South Africa -- Knysna , Sea horses -- Ecology -- South Africa -- Knysna
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54789 , vital:26616
- Description: The Knysna seahorse Hippocampus capensis is South Africa’s only endemic seahorse species, and is found in only three adjacent estuaries along the southern coast. The conservation of this endangered species is important on a national and international level. This study presents the first research on this species within the Knysna estuary since 2001 and specifically focuses on aspects of its ecology within a residential marina estate (Thesen Islands Marina). The physico-chemical and habitat features of the marina were described and the population ecology, habitat use, and behaviour of the Knysna seahorse were investigated. Physico-chemical conditions within the western section of the marina, characterised by high water current velocities, were similar to that of the adjacent estuary. The eastern section of the marina was characterised by lower water current velocities and higher turbidity. Four major habitat types were identified within the marina canals: (I) artificial Reno mattress (wire baskets filled with rocks); (II) Codium tenue beds; (III) mixed vegetation on sediment; and (IV) barren canal floor. Seahorse densities within the marina were significantly higher compared to densities found historically within the estuary. Highest seahorse densities were specifically found within the artificial Reno mattress structures and within the western section of the marina. Seahorse density varied spatially and temporally and the type of habitat was an important predictor for seahorse occurrence. An experimental investigation found that H. capensis chooses artificial Reno mattress habitat over Zostera capensis when given a choice. GoPro cameras were used successfully to investigate daytime seahorse behaviour within the Reno mattress habitat. Seahorses were more active during the morning, spent most of their time (> 80 %) feeding, and morning courting behaviour for this species were confirmed. However, during the summer holiday period (mid-December to mid-January) few seahorses were observed on camera, which suggests that the increase in motor boat activity and the related increase in noise had a negative effect on H. capensis feeding and courting behaviour. The marina development, and in particular the Reno mattresses, created a new habitat for this endangered species within the Knysna estuary. In addition to the protection and restoration of natural habitats in which H. capensis is found, the conservation potential of artificial structures such as Reno mattresses should be realised.
- Full Text:
- Date Issued: 2018
- Authors: Claassens, Louw
- Date: 2018
- Subjects: Endangered species -- South Africa -- Knysna , Sea horses -- Behavior -- South Africa -- Knysna , Sea horses -- Habitat -- South Africa -- Knysna , Sea horses -- Ecology -- South Africa -- Knysna
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54789 , vital:26616
- Description: The Knysna seahorse Hippocampus capensis is South Africa’s only endemic seahorse species, and is found in only three adjacent estuaries along the southern coast. The conservation of this endangered species is important on a national and international level. This study presents the first research on this species within the Knysna estuary since 2001 and specifically focuses on aspects of its ecology within a residential marina estate (Thesen Islands Marina). The physico-chemical and habitat features of the marina were described and the population ecology, habitat use, and behaviour of the Knysna seahorse were investigated. Physico-chemical conditions within the western section of the marina, characterised by high water current velocities, were similar to that of the adjacent estuary. The eastern section of the marina was characterised by lower water current velocities and higher turbidity. Four major habitat types were identified within the marina canals: (I) artificial Reno mattress (wire baskets filled with rocks); (II) Codium tenue beds; (III) mixed vegetation on sediment; and (IV) barren canal floor. Seahorse densities within the marina were significantly higher compared to densities found historically within the estuary. Highest seahorse densities were specifically found within the artificial Reno mattress structures and within the western section of the marina. Seahorse density varied spatially and temporally and the type of habitat was an important predictor for seahorse occurrence. An experimental investigation found that H. capensis chooses artificial Reno mattress habitat over Zostera capensis when given a choice. GoPro cameras were used successfully to investigate daytime seahorse behaviour within the Reno mattress habitat. Seahorses were more active during the morning, spent most of their time (> 80 %) feeding, and morning courting behaviour for this species were confirmed. However, during the summer holiday period (mid-December to mid-January) few seahorses were observed on camera, which suggests that the increase in motor boat activity and the related increase in noise had a negative effect on H. capensis feeding and courting behaviour. The marina development, and in particular the Reno mattresses, created a new habitat for this endangered species within the Knysna estuary. In addition to the protection and restoration of natural habitats in which H. capensis is found, the conservation potential of artificial structures such as Reno mattresses should be realised.
- Full Text:
- Date Issued: 2018
Assessing factors influencing professional nurses' attrition in South Africa : a case study of private hospitals in Johannesburg
- Authors: Mbobo, Angelina Pretty
- Date: 2018
- Subjects: Intensive care nursing
- Language: English
- Type: Thesis , Masters , Public Health Leadership
- Identifier: http://hdl.handle.net/10353/11181 , vital:37200
- Description: South Africa faces an immense shortage of healthcare professionals, especially trained and experienced critical care nurses. This thesis assesses factors influencing professional nurses ‘attrition in two selected private hospitals. This results in an HR risk; loss of skills, task shifting and the use of less skilled nurses, and not limited to the high workloads in intensive care units together with the job dissatisfaction consequently. To confirm this, a case study making use of a qualitative approach, follows the definition of a social constructivism framework. The study assessed 40 trained and experienced critical care nurses in focus groups of 5, with which a stratified purposive sampling technique was used and the focus group interviews were 90 minutes Seven structured interviews were undertaken, (using a narrative summary) with hospital operational managers working directly with the critical care nurses. Audio-recorded data were analysed by thematic content analysis using Creswell’s steps content analysis method. Multiple reasons, as given by nurses, to discontinue their services in private hospitals emerged. These were: Heavy workloads, shortage of trained staff, medico-legal risks; lack of supervision, support and teamwork, physical and emotional exhaustion, fatigue, stress and burnout, differential salary scales, non-competitive retirement packages role ambiguity, inadequate equipment, unresolved conflict with colleagues or management, personal financial crisis, lack of recognition and Lack of career development or promotion. These factors make use of themes, which include issues related to line management, administration, subjective and uncertainty of roles. Operational managers confirmed such reasons for the discontinuation of services offered by critical care nurses in private hospitals. Management views to the attrition of critical care nurses were that: (a) The staffing crisis was a serious matter of concern, (b) the use of less skilled staff resulted in negative effects on patient care and (c) the low number of critical care nursing staff negatively affected organisational goals.
- Full Text:
- Date Issued: 2018
- Authors: Mbobo, Angelina Pretty
- Date: 2018
- Subjects: Intensive care nursing
- Language: English
- Type: Thesis , Masters , Public Health Leadership
- Identifier: http://hdl.handle.net/10353/11181 , vital:37200
- Description: South Africa faces an immense shortage of healthcare professionals, especially trained and experienced critical care nurses. This thesis assesses factors influencing professional nurses ‘attrition in two selected private hospitals. This results in an HR risk; loss of skills, task shifting and the use of less skilled nurses, and not limited to the high workloads in intensive care units together with the job dissatisfaction consequently. To confirm this, a case study making use of a qualitative approach, follows the definition of a social constructivism framework. The study assessed 40 trained and experienced critical care nurses in focus groups of 5, with which a stratified purposive sampling technique was used and the focus group interviews were 90 minutes Seven structured interviews were undertaken, (using a narrative summary) with hospital operational managers working directly with the critical care nurses. Audio-recorded data were analysed by thematic content analysis using Creswell’s steps content analysis method. Multiple reasons, as given by nurses, to discontinue their services in private hospitals emerged. These were: Heavy workloads, shortage of trained staff, medico-legal risks; lack of supervision, support and teamwork, physical and emotional exhaustion, fatigue, stress and burnout, differential salary scales, non-competitive retirement packages role ambiguity, inadequate equipment, unresolved conflict with colleagues or management, personal financial crisis, lack of recognition and Lack of career development or promotion. These factors make use of themes, which include issues related to line management, administration, subjective and uncertainty of roles. Operational managers confirmed such reasons for the discontinuation of services offered by critical care nurses in private hospitals. Management views to the attrition of critical care nurses were that: (a) The staffing crisis was a serious matter of concern, (b) the use of less skilled staff resulted in negative effects on patient care and (c) the low number of critical care nursing staff negatively affected organisational goals.
- Full Text:
- Date Issued: 2018
Assessing grade 9 learners' attitude towards their academic performance in mathematics in Pinetown education district, KwaZulu-Natal
- Authors: Olorunfemi, Sunday Olayinka
- Date: 2018
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/8518 , vital:32859
- Description: The world education system is faced with many challenges. Learners’ performance in mathematics in particular is one of the main areas of concern. Over decades, Mathematics has become an indispensable tool in the march towards technological breakthrough. The use of Mathematics reveals how people deal with their various private, social, and civil lives. The indispensable implications of Mathematics in the society made it to become a compulsory subject in the primary and secondary education in most countries of the world. Nevertheless, despite its wide application of Mathematics in the society, there are still many learners particularly in secondary schools who struggle to achieve the best knowledge of Mathematics. As applicable to most countries of the world, the performance of learner in South Africa is not encouraging. For example, the performance of Grade 9 learners, Pinetown Education District in particular, is not improving. Attitude is one major factor identified among learners that gravely affects learner’s performance in Mathematics. The study adopted qualitative approach which is rooted in interpretive paradigm to frame and focus the study. Interpretive paradigm is consistent with the assumption that experience of the world is subjective and best understood in terms of individuals’ subjective meanings rather than the researcher’s objective definitions. The sample included 15 participants (which include three Mathematics educators and twelve Grade nine learners) selected purposefully across three secondary schools, with attitudes and performance as inclusion criteria. Data were obtained through classroom observations and semi-structured interviews conducted with the selected Mathematics educators and learners of the selected schools to obtain their views on the impact of the attitudes of Grade nine learners on their performances in the subject. The study found that the learners perceived difficulty in Mathematics because of the information that was passed to them through their parents or guardians, seniors and peers who have negative attitudes towards Mathematics; their previous performances at early grades; the nature of Mathematics itself; and that learners were not well prepared from primary schools. It was also indicated that many learners have negative attitude towards Mathematics whose behaviours in the classroom affected others who would have loved to enjoy Mathematics. The study also revealed that all stakeholders (the educators, school managements, policy makers and parents) have part to play in motivating the learners to engage more in Mathematics. Also the study found that qualified educators who will develop good and friendly classroom environment, employing a highly interactive teaching method and as well giving adequate homework and assignments to the learners are needed to teach Mathematics in secondary schools. The study revealed that learning resources are not made available to the learners. There study therefore potentially provides that, educators can help mould the learners with negative preset mind about Mathematics through their classroom behaviours. The study further provides that learning materials such as textbooks and other geometry tools be made available for the learners use at home. The study also, provides that consideration be given to Mathematics class in the morning hours. The study concluded by giving general recommendations for improving learners’ participation and attitudes towards learning Mathematics.
- Full Text:
- Date Issued: 2018
- Authors: Olorunfemi, Sunday Olayinka
- Date: 2018
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/8518 , vital:32859
- Description: The world education system is faced with many challenges. Learners’ performance in mathematics in particular is one of the main areas of concern. Over decades, Mathematics has become an indispensable tool in the march towards technological breakthrough. The use of Mathematics reveals how people deal with their various private, social, and civil lives. The indispensable implications of Mathematics in the society made it to become a compulsory subject in the primary and secondary education in most countries of the world. Nevertheless, despite its wide application of Mathematics in the society, there are still many learners particularly in secondary schools who struggle to achieve the best knowledge of Mathematics. As applicable to most countries of the world, the performance of learner in South Africa is not encouraging. For example, the performance of Grade 9 learners, Pinetown Education District in particular, is not improving. Attitude is one major factor identified among learners that gravely affects learner’s performance in Mathematics. The study adopted qualitative approach which is rooted in interpretive paradigm to frame and focus the study. Interpretive paradigm is consistent with the assumption that experience of the world is subjective and best understood in terms of individuals’ subjective meanings rather than the researcher’s objective definitions. The sample included 15 participants (which include three Mathematics educators and twelve Grade nine learners) selected purposefully across three secondary schools, with attitudes and performance as inclusion criteria. Data were obtained through classroom observations and semi-structured interviews conducted with the selected Mathematics educators and learners of the selected schools to obtain their views on the impact of the attitudes of Grade nine learners on their performances in the subject. The study found that the learners perceived difficulty in Mathematics because of the information that was passed to them through their parents or guardians, seniors and peers who have negative attitudes towards Mathematics; their previous performances at early grades; the nature of Mathematics itself; and that learners were not well prepared from primary schools. It was also indicated that many learners have negative attitude towards Mathematics whose behaviours in the classroom affected others who would have loved to enjoy Mathematics. The study also revealed that all stakeholders (the educators, school managements, policy makers and parents) have part to play in motivating the learners to engage more in Mathematics. Also the study found that qualified educators who will develop good and friendly classroom environment, employing a highly interactive teaching method and as well giving adequate homework and assignments to the learners are needed to teach Mathematics in secondary schools. The study revealed that learning resources are not made available to the learners. There study therefore potentially provides that, educators can help mould the learners with negative preset mind about Mathematics through their classroom behaviours. The study further provides that learning materials such as textbooks and other geometry tools be made available for the learners use at home. The study also, provides that consideration be given to Mathematics class in the morning hours. The study concluded by giving general recommendations for improving learners’ participation and attitudes towards learning Mathematics.
- Full Text:
- Date Issued: 2018